Fuel systems for internal combustion engines powering outboard motors typically include a vapor separator. In these fuel systems, fuel is supplied from a tank to the vapor separator. A high pressure pump delivers the fuel from the separator through a fuel rail to individual fuel injectors.
Fuel which is supplied to the fuel rail but not distributed by the injectors is preferably re-routed back into the fuel system. Because the undistributed fuel is agitated, it may contain air bubbles and is thus passed into the vapor separator. The vapor separator is designed to allow the air within the fuel to separate from the fuel, which fuel is then routed back into the fuel delivery line to the fuel injectors.
In order to reduce corrosive effects upon the various fuel system components, oil is preferably supplied into the fuel for distribution through the fuel system. The oil may be used to lubricate the passages, springs, plungers and other fuel system components.
A problem arises from the fact that oil has a higher specific gravity than the fuel, and as such, the oil may settle to and remain at the bottom of the vapor separator. In addition, when the watercraft is accelerating, the settled oil may be drawn to that portion of the separator opposite the high pressure fuel pump intake. When the oil is so located, and because once separated it resists flow, the high pressure pump is unsuccessful in drawing oil along with fuel from the vapor separator.
A fuel system including a vapor separator adapted to separate vapor from fuel and from which a well-mixed supply of fuel and oil may be drawn, is desired.